Semiconductor light-emitting devices including but not limited to light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), and edge emitting lasers are among the most efficient light sources available. Materials systems used in the manufacture of high-brightness light emitting devices that are capable of operation across the visible spectrum include Group III-V semiconductors. LEDs that emit blue light may be formed from binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, which are also referred to as III nitride materials. LEDs that emit red light may be formed from binary, ternary, and quaternary alloys of gallium, aluminum, indium, arsenic, and phosphorus.
Light emitting devices may be fabricated by epitaxially growing a stack of semiconductor layers of different compositions and dopant concentrations on a GaAs, sapphire, silicon carbide, III-nitride, III-phosphide, III-arsenide, silicon, or other suitable substrate by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. The stack of semiconductor layers may include one or more n-type layers doped with, for example, Si, formed over the substrate, one or more light emitting layers in an active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, Mg, formed over the active region. Electrical contacts may be formed on the n-type and p-type regions.